The interest in the effects of drinking during pregnancy has grown rapidly following the early publications on the fetal alcohol syndrome by Jones and Smith in 1973. The results of various studies to date suggest an adverse relationship of heavy maternal alcohol use during pregnancy on the offspring. There still remains, however, some unanswered questions such as: "What is the effect of moderate drinking on the offspring? What are the possible synergistic effects of alcohol use with other substances such as smoking? What are the long term development effects of maternal alcohol use on the offspring? Does termination of maternal drinking during the early stages of pregnancy reverse possible adverse effects on the offspring? A five-year prospective study of 1,320 children ages 2 to 5 is proposed to provide information to help answer these questions. The 1,320 children are to be selected from an ongoing study of 10,000 pregnant women on whom we already have extensive prenatal, labor delivery and birth information. For each participate we will annually assess the home environment, parent-child interactions, demographic and psychosocial factors by means of a home interview. Physical and mental characteristics on each child will be assessed by a pediatric nurse and a psychometrician at the first and fourth year at a visit to our clinic. The study design calls for three different comparison groups which will provide data to determine the role that alcohol use during pregnancy played on subsequent development characteristics. By being able to provide data concerning the possible harmful effects of drinking during pregnancy on the offspring, information will be made available that can be used to initiate prevention programs to hopefully reduce morbidity and disability and cut the cost of care of premature infants in the community.